The term non-allergic rhinitis (“NAR”) is generally applied to a diagnosis where symptoms of allergic rhinitis are present without allergic etiology or IgE involvement. NAR encompasses a heterogeneous group of conditions with varying etiologies, including vasomotor rhinitis, non-allergic non-infectious perennial rhinitis, occupational rhinitis, drug-induced rhinitis, hormonal-induced rhinitis, non-allergic rhinitis with eosinophilia syndrome, gustatory rhinitis and emotion-induced rhinitis (See: Bachert C (2004) Persistent rhinitis—allergic or non-allergic? Allergy 59 (Suppl. 76): 11-15). A diagnosis of NAR is often made when subjects with negative skin prick testing for a panel of allergens present with persistent nasal symptoms (more than nine months a year) including at least two of the following: hypersecretion, blockage, sneezing or post-nasal drip. Subjects typically have one symptom that predominates and can be classified into: runners for those in which hypersecretion predominates; or blockers for those in which congestion predominates.
Within a rhinitis population, it has been estimated that approximately twenty-three percent (23%) of the population have pure NAR (characterized by nasal symptoms but a negative skin prick test) and thirty-four percent (34%) of the population have mixed rhinitis (a combination of allergic and non-allergic). While not a life threatening illness, the impact of NAR on quality of life is significant and includes impaired sleep, increased daytime drowsiness, decreased ability to concentrate, and increased irritability (See: Svensson S, Olin A C and Hellgren J (2006) Increased net water loss by oral compared to nasal expiration in healthy subjects. Rhinology. 44: 74-77).
Numerous triggers of NAR have been identified. Such identification has primarily involved subject reporting. NAR triggers can be classified into various groups such as weather changes, airborne irritants, emotions and food or alcohol. Weather changes include changes in temperature, humidity or barometric pressure; in particular, cold dry air and warm moist air have been identified as strong triggers (See: Brandt D and Bernstein J A (2006) Questionnaire evaluation and risk factor identification for nonallergic vasomotor rhinitis. Annals Allergy Asthma & Immunol. 96: 526-532). Numerous airborne irritants have been identified as common triggers of NAR including perfumes and colognes, household cleaning products, incense, hairspray, tobacco smoke, car exhaust, acetic acid and capsaicin spray. Spicy foods and alcohol intake have also been identified as risk factors for NAR.
Clinical models to increase an understanding of NAR, or to test putative NAR therapies are currently not available. Consistently NAR subjects report that their symptoms are primarily provoked by key environmental triggers such as cold dry air (CDA), fragrance, pollution (e.g. ozone may be an important element of pollution), and aerosolized irritants. Presently there is no consensus on specific environmental triggers that evoke nasal symptoms in pure NAR subjects. Previous attempts to diagnose NAR triggers predominantly involved questionnaire approaches.
Utilizing a chamber having an inlet for allergen test particles is known in the prior art to test subjects for allergic reactions to a specific allergen, for example as disclosed in US Patent Application No. 2004/0054262. This patent application discloses an allergy test chamber. The chamber comprises at least one inlet for allergen test particles, so that a defined quantity of allergens may be mixed with allergen-free air and allergen particulate-loaded air may be circulated in the test chamber.
US Patent Application No. 2007/0286804 further discloses a chamber in which airborne particulates relating to testing for a particular allergen are aerosolized and kept within strict limits. Said chamber is a level II clean room, having seating capacity for 60 subjects. The chamber comprises a means of controlling humidity and temperature which includes clean air vents as well as air inlets and outlets fitted with HEPA filters. Other aspects of the chamber are specifically configured for the purpose of testing allergic reaction of a subject to dust-mite allergens including walls covered with statically dissipative paint, rounded corners and baseboards, and a floor covered with smooth, resilient, sheet flooring with few seams.
Other containment chambers operable to create a specific atmosphere within the chamber are also known generally in the prior art. These containment chambers are not utilized for the purpose of allergy or NAR testing. Such chambers include that disclosed in U.S. Pat. No. 7,323,025 (and U.S. patent application Ser. No. 2005/0050804) which comprises a sleeve air exchange, an airlock entrance, a HEPA filter, a pressure control means, and a UV radiating unit; wherein a subject requiring isolation may be positioned to achieve containment of an infectious disease. U.S. Pat. No. 7,335,243 further discloses a modular negative pressure biological containment chambers having HEPA or ULPA filters, double entry portals and modular chamber panels; whereby biological materials may be contained. U.S. patent application Ser. No. 2008/0210234 discloses a variable pressure chamber having an air-tight container, a sealable opening, a viewing window, chairs for subjects, space for multiple subjects inside the container, dual lock entry, an air flow means, a pressure monitoring and control means; whereby a subject may be positioned within the container and the pressure may be adjusted within the container in accordance with a desired subject within the container for the purpose of treatment of the subject.